Described below is a system for the precise time synchronization of network subscribers of a network based on satellites.
Such a system is intended for applications in which satellite systems such as, for example, the US's GPS system, Russia's GLONASS, China's COMPASS, Europe's GALILEO and other similar systems, are used to synchronize their use in relation to time, or reference time, using the time data available from these systems, it being possible for this synchronization of the system normally to take place via an Ethernet infrastructure. For many applications, the requirements are such that they require a precise reference time, and errors in synchronization lead to serious malfunctioning of the system as a whole. Also, such applications may be located in an environment where there is a high level of interference.
Until now, such systems for time synchronization based on satellites are achieved in two phases: a first phase consists of a satellite antenna and, if necessary, an integrated high frequency amplifier for the satellite signal. This phase is typically mounted externally. This signal is then fed inwards into the application via separate wiring (typically coaxial). A second phase is mounted internally (typically, in a switch cabinet). The satellite signal (in certain circumstances, amplified) is fed to it via the wiring. This phase contains the electronic system for capturing the required time from this signal, and either contains a network connection directly or makes available the time of another phase with a network connection. Synchronization of use was achieved via the network connection using network protocols. This being the case, the delay between phase 1 and phase 2 must be compensated for in order that the reference time be precise. In addition, EMC (electromagnetic compatibility) protection for the coaxial infrastructure is problematic. The usability of existing solutions as regards precision, reliability and interference resistance is currently the subject of research.